DETROIT, MI, May
17, 2000 – Results of a two-year design study of
automotive suspensions released today showed mass reductions of up to 34
percent at no increase in cost for four steel-intensive designs,
compared to a range of benchmarked steel suspensions. The study also
included a fifth steel design that showed a 30 percent cost reduction
with a small mass reduction, compared to a current aluminum
design.

All five
designs meet or exceed a range of performance criteria including those
for ride and handling and NVH (noise, vibration, harshness),
manufacturability and packaging (the effect on underbody, occupant and
luggage space).

Sponsored
by a consortium of 34 of the world’s leading steel companies and
conducted by Lotus Engineering Services, Inc., England, the UltraLight
Steel Auto Suspension (ULSAS) study demonstrates how the use of
iterative, holistic design, coupled with innovative use of high- and
ultra high-strength steel sheet, tubular and bar products, and advanced
manufacturing technologies can result in lighter weight, lower cost and
better performing vehicle suspension systems.

The
program is a companion to the UltraLight Steel Auto Body (ULSAB) study
released in 1998, the UltraLight Steel Auto Closure (ULSAC) study, which
is nearly complete, and ULSAB-AVC (Advanced Vehicle Concepts) study,
which will be complete in 2001.

Peter
Rawlinson of Corus Group – UK and Nick Sampson of Lotus
Engineering Services, Inc., today on behalf of the ULSAS Consortium
presented the results of the program at the Society of Automotive
Engineers Automobile Dynamics and Stability Conference in
Detroit.

"As was
the case with ULSAB, ULSAS shows the potential of steel to reduce
weight, lower costs and improve performance," said Darryl C. Martin,
senior director, Automotive Applications, American Iron and Steel
Institute (AISI). "For our vehicle-making customers, these criteria are
foremost. We look forward to meeting with them to help them understand
how they can incorporate in their suspension designs the advanced
concepts that ULSAS demonstrates."

Extensive
use of high- and ultra high-strength steels in all five designs made
possible the substantial mass reductions. Also contributing to mass
savings, as well as to cost savings and performance enhancements, are
strategic use of large, thin-wall sections, hydroforming, tailored
blanks and laser welding.

From a
design standpoint, Lotus Engineering rigorously pursued opportunities
for part consolidation and strategies to promote ease of manufacture and
lower tooling costs. The design team also relied heavily on
representatives of the steel companies, who early in the program
provided expertise and advice concerning the steels, cost analysis and
forming simulations.

Lotus
benchmarked a representative, comprehensive range of automobiles from
Europe, Asia and North America. Against these benchmarks, Lotus
engineers designed five different rear suspensions, each advancing the
state of the art of its respective type.

The
Twistbeam design was the star of the show – with mass savings up
to 32 percent at somewhat less cost. The design differs from
conventional twistbeams because it features a transverse beam of
thin-wall tube uniquely profiled to save weight. It sweeps in a U shape
that provides continuity of structure from hub to hub. The design uses
high-strength steel in the U-shaped tube, trailing arm, spring pan,
springs and hub mounting plate. The two forward facing arms are
hydroformed. The twistbeam design substantially exceeded benchmark
performance targets.

This type
of rear suspension is common in smaller cars, where passenger and
luggage space is critical but ride quality is less so. However, because
the design would perform significantly better than any of the
benchmarks, it could be a leading suspension option for future small
cars where good handling, as well as space and packaging, are key
criteria.

The Strut
& Links design achieved mass savings of 25 percent through extensive
use of high- and ultra high-strength steels, coupled with an iterative
design approach to optimize components. The design also achieved
slightly lower cost and target-exceeding performance, and met all other
target criteria.

Strut and
links designs usually represent a low-cost approach with compromises in
ride and handling and in vehicle refinement.

The
Double Wishbone design achieved a mass saving of 17 percent with no cost
penalty, while exceeding performance targets. All parts are high- and
ultra high-strength steel and the design features a stamped
high-strength steel fore and aft arm and forged steel upright, rather
than a cast iron upright in the benchmark design.

Because
they represent a reliable overall compromise, double wishbone
suspensions often are used in sports cars.

The
Multi-Link design is the only concept in the study whose benchmark is
aluminum intensive. This suspension demonstrated a cost saving of 30
percent while showing a slight mass advantage compared with its
aluminum-intensive benchmark. All major parts are of high- and
ultra-high-strength steel. It matched the other target
criteria.

Multi-link suspensions are more sophisticated and costly than
the others in the study, but provide superior ride and handling and
vehicle refinement.

Lotus
also designed a Lotus Unique concept, which resulted in mass savings of
34 percent and a modest cost advantage compared to a conventional double
wishbone system, to which it is similar. Created from a clean sheet and
specifying the latest in steel materials and technologies, this design
offers performance advantages of more complex suspension systems, while
simplifying and minimizing the number of components. Featuring extensive
use of high- and ultra-high-strength steel, the design exhibits good
performance with a relatively efficient package. The study showed it
would be easy to manufacture and assemble.

Lotus
conducted the ULSAS project in two phases. First, Lotus engineers
carried out a comprehensive benchmark study to test and evaluate
suspensions in a variety of vehicles from North America, Europe and
Asia. The process included road and track testing, detailed design
reviews and weight, cost and manufacturing studies.

Based on
those assessments, Lotus undertook a holistic review of suspension
system requirements, identified opportunities for application of new
steel technologies and established an extensive range of targets for the
design phase of the ULSAS project.

ULSAS
focused on rear suspensions because:

Although
both front and rear suspensions have equal potential impact on vehicle
handling and performance, rear suspensions have greater impact upon
occupant and luggage space.

Most
front suspensions on cars worldwide are of the McPherson strut design,
whereas different size and class cars from different automakers use a
wide variety of rear suspension types.

Lightweighting, cost-saving and performance-improving concepts
developed in the study could apply equally to front
suspensions.

The
Automotive Applications Committee (AAC) is a subcommittee of the Market
Development Committee of AISI and focuses on advancing the use of steel
in the highly competitive automotive market. With offices and staff
located in Detroit, cooperation between the automobile and steel
industries has been significant to its success. This industry
cooperation resulted in the formation of the Auto/Steel Partnership, a
consortium of DaimlerChrysler, Ford and General Motors and the member
companies of the AAC.